The popular Tang dynasty theme park, Tang Paradise, in central China’s Shaanxi Province, Xi’an, attracted massive attention online after it announced a limited-time free pass offer to the first 618 female visitors.

Tang Paradise gave away the free tickets from June 15-19, just in time for the Dragon Boat Festival on June 18, according to Shanghaiist.

While the offer sounds enticing, the requirement to be eligible is not something one can achieve instantaneously. In the video shared by Btime, the park posted a sign that reads, “Free entry for ladies of the Tang dynasty.”

This means that only women who weigh over 61.8 kilograms (136 pounds) can gain free entry into the theme park. They must get their weight checked by an oversized scale with a 61.8-kilogram block on the other end. If they manage to tip the scale, they will be considered a proper Tang dynasty woman.

Those who fail the weigh-in test but still want to enter the theme park will have to cough up 90 yuan ($13.84) for a ticket.

The beauty standards during the Tang dynasty (618–907) were completely different from today’s society. Women who weighed a bit more were regarded as someone from a wealthy household.